File - In this April 20, 2010 file photo, a large marijuana joint is lit at Golden Gate Park in San Francisco. Thursday, April 20, 2017, marks marijuana cultures high holiday, 4/20, when college students gather - at 4:20 p.m. - in clouds of smoke on campus quads and pot shops in legal weed states thank their customers with discounts. (AP Photo/Marcio Jose Sanchez, File)
